When they are in Las Vegas, the view out the window clearly shows the circular hotel tower of the old Sands hotel and casino, which was imploded in 1996, despite the fact that the film obviously takes place in 2009.
When Aldous and Aaron leave London to fly to New York, a twin engined Boeing 767 shown. However when they land in New York, a four engined Boeing 747 is shown landing. London to New York flights tend to be nonstop, so they wouldn't have changed planes. Also when they fly to Vegas, they take off in a Boeing 757 and land in an Airbus A320, and the planes have different company liveries.
The night of his concert at The Greek, Aldous suffers a compound fracture in his left arm where bones are sticking out of his skin. At the Storytellers concert six months later, he has no visible scars on his arm.
When Aaron calls Daphne from the club and he starts to argue with her, she is drinking a beer and pacing in front of the kitchen window. Several members of the film crew are visible in the reflection from the window.
When Aldous is performing outside at the Today Show, a blue cherry picker is visible behind him with a distinctive Panavision 35mm movie camera and crewmembers on it. Several shots from this camera are used in the sequence.
Aaron and Aldous are seen flying from London to New York using Stansted Airport (it is not identified in the movie). Stansted has no passenger services to any American city, but it is logistically much easier to use as a filming location than either Heathrow or Gatwick.